Questions tagged [web3js]

Javascript API and library for Ethereum
To develop applications on Ethereum, you can use the web3 object provided by the web3.js library. Under the hood it communicates to a local node through RPC calls. web3.js works with any Ethereum node, which exposes an RPC layer.
https://github.com/ethereum/wiki/wiki/JavaScript-API

I am developing a dApp that is parsing an ABI and then it shows the functions of it and fields that is for every function's variable and i want to send the function with its variables to MetaMask to ...

i'm getting { [Error: Node error: {"code":-32000,"message":"leveldb: not found"}] when trying to use events on a private eth blockhain.
What might be the problem? (I've installed Leveldb with brew)
...

The function I am accessing will emit events i need to use that event but the function is a transaction when i am accessing the event it turns as promise pending . So suggest me some methods. thanks!
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I have a blockchain deployed in a cluster. I have a geth instance running in a cluster-node and another one in another cluster-node, making a blockchain. I want to run an script which needs to access ...

I'm trying to get a list of unique addresses that have interacted with a contract. As well as some data included in the events of each transaction. In order to do this, I use the action=getLogs query ...

a quick beginner's question... is it possible to sign a message twice with web3? For example Alice creates a message and signs it. Then it is sent to Bob. Can Bob sign the message before he executes ...

The project is a truffle-react trufflebox, a bounties creating and solving application. It uses Truffle v5.0.1. This is the home page.
Below is the page that displays when you click on the 'Become a ...

I am trying to call a function in another contract, that is protected with an openzepellin Role library.
I am calling availableFunction on the javascript side, which in turn calls protectedFunction. ...

I am starting a project that I need to build a solution to track products (ex: from farm until it gets to the supermarket)
Basically, I need to set up a blockchain structure for my company(private) ...

I am running a lightmode geth daemon, and I want to check the balance of my daemon. I read this answer, which says that I cannot use the command that I am currently using, as it requires support for ...

I have deployed the smart contract of Payment channel and every thing is working fine but at the time of closing the channel signature is not being validate.
I think passing the arguments in a wrong ...

On a locally hosted instance of Ethererum I am trying to replay and understand the Bad Parity hack. I have a Wallet and a Wallet Library Contract.
Wallet.sol
constructor(address lib) public payable {...

I'm calling a function that will write information to contract, and MetaMask will list it as a 'Contract Deployment'. It is on the Rinkeby testnet. But if I run it locally using Truffle/Ganache, it ...

I'm trying to write a code that reads variable, adds 1, sends update call, waits until the transaction is done and then reads the variable again.
Console shows that the transaction is complete, but ...